/Engine/Plugins/Animation/ControlRig/Source/ControlRig/Public/Rigs/RigHierarchyController.h
Removes an existing parent from an element in the hierarchy. For elements that allow only one parent the element will be unparented (same as ::RemoveAllParents)
Returns true if successful.
bool RemoveParent &40; FRigBaseElement &42; InChild, FRigBaseElement &42; InParent, bool bMaintainGlobalTransform &41;